


Hard Boiled

by ozuma



Category: Captain America (Movies), Iron Man (Movies), Marvel Cinematic Universe, The Avengers (Marvel Movies)
Genre: Aftercare, Anal Sex, Barebacking, Belly Kink, Bottom Steve Rogers, Butt Plugs, Dom/sub Undertones, Egg Laying, Fluff and Smut, For Science!, Kink Negotiation, Light Bondage, M/M, Medical Kink, Multiple Orgasms, Nanites, Nanotechnology, Oviposition, Plot What Plot/Porn Without Plot, Praise Kink, Riding, Safe Sane and Consensual, Smut, Technobabble, Top Tony Stark
Language: English
Status: Completed
Published: 2019-01-16
Updated: 2019-01-16
Packaged: 2019-10-10 20:11:05
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 10,799
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17432735
Author URL: https://archiveofourown.org/users/ozuma/pseuds/ozuma
Summary: “Is that what I think it is?”“Not an egg,” Tony said with a smile, like he was reading Steve’s mind. “It’s what I’ve determined to be the best shape for what we’ll be doing. So it’s shaped like an egg, but it is definitely anything but.”“I don’t have to eat one, do I?”Tony’s expression turned downright devious. “They’re not going in that end.”Steve could feel his eyebrows practically hit his hairline. He shouldn’t have been surprised, and, well, thiswasTony. “I think I’m starting to understand this a bit better.”To satisfy Steve's super soldier libido, Tony comes up with a new use for some experimental nanotechnology. Despite being uneasy at first, Steve eventually reaps the benefits.





	Hard Boiled

**Author's Note:**

> I continue my trend of kink fic with oviposition this time! I'm pretty sure I got this idea while talking with other people on the Stony Discord about kink. So as always, I'm thankful to everyone on that server for being so helpful and inspiring.
> 
> Thanks also to my cheer reader [FreyaS](https://archiveofourown.org/users/freyas) and beta [brokeneisenglas](https://archiveofourown.org/users/brokeneisenglas)!
> 
> While this fic does reference some actual science, I'm not going for complete accuracy. Apologies for any inaccuracies in the following story. All research was done for the purpose of sexy fun times.

Steve groaned, burying his head into the warm pillow as Tony continued to work his hand on his cock. The slide of Tony’s hand was slick and easy thanks to the amount of lube, precome, and come that had built up over the series of Steve’s half dozen orgasms in the past couple of hours. In the back of his mind, beyond the pleasure that was singing through his nerves at the moment, he actually felt somewhat guilty. Tony had fucked him three times with dildos of increasing size, then fucked him with his own cock, and then after that he’d sucked him off twice. And yet more than two hours after they had started, Steve was still worked up and horny as hell. His refractory period was still under five minutes, and Steve himself felt like he’d never be satisfied.

“Tony, Tony…” he gasped into the pillow that was already damp with sweat and saliva. “I’m so close.”

“You’d better be,” Tony mumbled from behind him as his hand worked Steve’s dick faster. “Pretty sure my calluses are getting calluses at this point.”

Steve could hear Tony breathing heavily right by his ear. He was clearly starting to wear out; a fact that Steve’s sex drive was unfortunately indifferent to.

A few moments later, Steve came with a soft moan, his release somewhat decreased compared to the last few orgasms, but still more than would be considered normal. As Steve panted into the pillow, his hands gripping the bed sheets tightly, he waited until he was settled enough to get out a full sentence.

He turned his head so he could just see Tony. “I’m done. Really, Tony.”

Tony raised a skeptical eyebrow in response. “You’re already stiffening up in my hand, champ.”

“I’m good for tonight. I mean it.” He could let it go down on its own. It was uncomfortable, but he’d live.

Tony hummed against the skin between Steve’s shoulder blades. “One of these days I’m going to figure out how to crack that supersoldier libido of yours.”

Steve huffed out a laugh. “I’m not an engineering problem, Tony.” That was one thing he was learning about Tony in their relationship: he could take anything as a challenge.

“You basically are!” Tony’s hand moved away from his cock and up toward his chest instead. Steve swallowed his moan of protest at the loss. That would just encourage Tony to keep being stubborn. “Haven’t had the time to work on that fucking machine I mentioned a while ago, but the design in my head is complete.”

Steve’s laughter turned nervous. With Tony, chances were that he’d walk into the workshop the next day and find Tony working on an actual fucking machine.

Steve reached back to pat Tony’s side. “I’m not going to die from lack of orgasms, Tony. Really, it’s fine.”

He could feel Tony shake his head. “Nope, we’re going to figure this out. I’m going to wear you out until your dick throws in the towel.” His arms tightened around Steve. “Honestly, I’d be working on a prototype if I wasn’t so busy with the latest upgrades to the team’s gear and that project I’ve been collaborating on with Dr. Cho…” Tony’s voice drifted off for a second, and his body stiffened against Steve’s.

“Tony?”

“Huh.” There was a pause that felt ominous to Steve.. “Can’t believe I didn’t think of this earlier! It just might work…”

This was getting to be too much. Steve finally pulled away so he could turn around and really face Tony. Once he saw that thoughtful expression on Tony’s face, he knew this was trouble.

“ _What_ might work?”

Tony’s gaze locked with Steve’s, though his expression was no longer flirty and lust-filled. He had the same look in his eyes that he had whenever he started on a new version of the Iron Man armor.

Tony leaned back on his elbows, his earlier frustration seemingly forgotten. “Tell me: what’s your favorite part of getting fucked?”

Steve could feel his face heating up. Tony’s dirty talk was downright dangerous. “Um… all of it? You’re kind of putting me on the spot, here.”

Laughing, Tony said, “Well, let’s go by process of elimination.”

Steve took a moment to think it over. “I guess I just really enjoy… the feeling?” He added, hastily, “Especially when it’s a lot.”

“Like that time I got my fist up your ass you came three times in ten minutes?” Tony asked.

Steve ran a hand over his face, which he knew must be beet red, by now. Ducking his head a bit, he let his gaze drift to the rumpled bed sheets behind Tony as he thought back to that night. Every slight movement of Tony’s hand inside of him had sent sparks of pleasure racing through him. Once Tony had gotten his hand all of the way inside of him and against his prostate, he’d barely lasted another thirty seconds. It had been one of the best orgasms of his life and one of the few times he’d gone to bed feeling truly sated.

Even then, though… Steve had always wondered what it would be like to be even more full than that. If it was even possible.

“Do I want to know where this is going?”

Tony grinned and reached a hand up to cup Steve’s cheek, forcing Steve to look back at him. “I’ve got a plan, Steve. A plan to finally satisfy your super sex drive.”

Steve felt his cock twitch just at the thought of it. Generally, Tony declaring he had any plans in the context of the bedroom led to very good nights for Steve.

“Am I going to like this plan?”

Tony gave him an all-too-familiar smirk. “You are going to _love_ it, handsome.”

 

* * *

 

Tony loved to tease Steve about his inexhaustible libido. Even after everything Dr. Erskine had explained to him about the effects of the super soldier serum, Steve had never considered that “peak of human perfection” would also apply to his sex life. He supposed there might be an evolutionary advantage to having almost no refractory period. But on an actual individual level, it was a goddamned pain to deal with. His hand alone was never enough to satisfy him. After waking up from the ice, one of his favorite things about the future was the sheer variety of sex toys available and all of the discreet ways to purchase them. And even then vibrating dildos only did so much for him.

When he’d started sleeping with Tony… well, Tony always insisted on making sure his partners were satisfied.

The first time he’d felt Tony inside of him, he thought he was going to combust. No state of the art dildo could have prepared him for the experience of sex with an actual person. Tony had figured out Steve was incredibly sensitive pretty much from the get go and mercilessly took advantage of that knowledge to drive Steve to incoherence.

_They were lying together after Tony had wrung a truly impressive number of orgasms out of him, when Tony had turned to Steve with a big, goofy grin on his face._

_“Steve, you are_ such _a cock slut,” Tony had declared like it was some great revelation._

_Steve was taken aback at first because that sure as hell didn’t sound like a compliment to him. His expression must have given his thoughts away, though, because Tony had moved closer before explaining what he meant._

_“Not an insult.” He planted a kiss over his collarbone to emphasize his feelings. “Coming from me in this context? That’s about as high a compliment as I’d give anyone. You take cock like a champ. It’s almost a crime how amazingly you take it.”_

_“More of that twenty-first century lingo I need to catch up on, huh?” Steve had replied, trying for levity._

_“Nah. Anyone else calls you that and you punch them in the face for sure.”_

_Steve had laughed and pulled Tony closer for a kiss after that._

Since then, Tony practically made blowing Steve’s mind (among other things) in bed a side job.

The thing was, Steve enjoyed getting fucked. Absolutely loved it. While he was thankful for the strength the serum had granted him, sometimes he wanted to let go. Tony had recognized it, too. The way that Steve naturally took charge in the field. How Steve sometimes just wanted to get away from that in his down time. In bed, he could trust Tony to take care of him. To direct his considerable strength toward the purpose of their mutual enjoyment.

Tony was all too happy to indulge him. At first, he’d had a field day with Steve’s practically non-existent refractory period. Even when Tony had hit his own limit, he did everything he could to find ways to keep Steve sated. Steve remembered feeling guilty those times he’d gotten off from a really nice vibrating dildo (custom-made by Tony) for the fourth or fifth time only to look down and find that he was still hard.

Guilt was unfortunately something he was all too familiar with in bed. The few times they switched, Steve could keep fucking Tony for hours, even into a second orgasm. As great as that was, it always left Tony sore the day after. No matter how much he insisted it was okay, Steve would once again feel that familiar guilt.

This new plan of Tony’s apparently dealt with all of that, or so he assumed from Tony’s excitement over the whole project.

 

* * *

 

Steve finally managed to get some actual information out of him after one of their weekly team meetings. Tony had just shown off a new design for some of the team’s weapons to solicit some input, and now that they were finished and the rest of the team had left, well...

He glanced back at the workshop’s entrance to make sure they were alone before asking, “So how’s that mystery project coming along?”

Tony’s shift from project planning mode to mischief was as plain as day as he leaned back against a workbench. “It’s supposed to be a surprise!” he answered in a sing-song voice.

“Can’t even tell me a little bit about what you’re planning?”

Tony looked as though he was thinking it over before answering, “Fine.”

“I know that it has to do with nanotechnology?” Steve offered.

“Exactly,” Tony said. “The idea is that you can inject thousands of these tiny nanites into people and they can take measurements far more efficiently than taking a sample and sending it to a lab. At the moment we’re just testing how accurate those measurements are.”

“What does this tech have to do with your plan?”

Tony grinned. “Well, since you’ve asked so nicely.” He brought up a hologram showing what must have been some of the designs for the nanites. “The whole point of using nanotech like this is that it’s very flexible. It’s pretty easy to design nanites to play nicely with human body chemistry. That flexibility is what we need in this situation. They can form up into larger structures and change shape as needed to move throughout the body.”

“So you’re going to inject them into me…?” Steve wasn’t sure he liked the idea of being a guinea pig again.

Tony seemed to notice his uncertainty. He shook his head. “In this case, we won’t be using them for testing purposes, really. More for…” He rubbed his chin thoughtfully. “Well, more for the purpose of pleasure.”

“Wait, what?”

Tony went into an explanation of his plan for finally satisfying Steve’s supersoldier libido. Since he clearly got off on the feeling of being full, Tony claimed that he was going to use the nanotechnology for exactly that purpose.

“If you put them inside me…” Steve couldn’t help feeling off-kilter. “How… are they going to come out?”

Tony shrugged. “However you want to get them out. Like I said, they’re flexible.”

This had to be one of the weirdest conversations Steve had ever had in his life. “And this… won’t hurt?”

“Of course not,” Tony assured him. “These have already proven safe in clinical trials. I’m just tweaking them a bit for this.”

He made some complicated hand gesture, which changed the hologram to something that looked like… an egg?

“Is that what I think it is?”

“Not an egg,” Tony said with a smile, like he was reading Steve’s mind. “It’s what I’ve determined to be the best shape for what we’ll be doing. So it’s shaped like an egg but it is definitely anything but.”

“I don’t have to eat one, do I?”

Tony’s expression turned downright devious. “They’re not going in that end.”

Steve could feel his eyebrows practically hit his hairline. He shouldn’t have been surprised, and, well, this _was_ Tony. “I think I’m starting to understand this a bit better.”

“Good!” Tony closed the diagram. “So you still want to try, right?” He glanced up at Steve slowly in an expression that Natasha had once dubbed ‘the puppy dog eyes.’

Steve liked to think he had built up some resistance to that look, yet at the moment he wasn’t so sure. He told himself that he at least knew he could trust Tony, especially in something as… uniquely intimate as this. “I guess… we could give it a try.”

Tony’s face lit up immediately. “You won’t regret it, Steve. I promise you. It’s like the ultimate dildo… combined with an enema but without the mess!”

Steve just stared at him after that, the silence stretching on into uncomfortable territory.

“Okay, so maybe that wasn’t the best sales pitch. But trust me on this, Steve. This will be _amazing_.”

“Do I need to be prepared before we do… all this?”

Tony gave him an impish grin. “Oh, you know… Clean yourself out, medium-sized buttplug. The usual.”

Steve could feel his face heating up at Tony’s casual mention of all of that. At this point, he was used to it enough that it could be called ‘the usual’ without much exaggeration. “Sure. Just… let me know when you need me to.”

“You are so hot when you get bashful over this stuff, you know that?”

Steve pulled him close. “And you’re hot when you’re planning ridiculous things like putting nanites in my rear.” He cut off Tony’s laughter as he kissed him.

 

* * *

 

The lines on the page in front of him blurred as Steve’s eyes unfocused. He’d been on edge all afternoon, ever since Tony had instructed him to keep himself nice and open for what he had planned. While this wasn’t his first time using a butt plug, this was his first time keeping it in for more than an hour or two.

He was so damned sensitive that it was almost impossible to ignore. As much as he wanted to be good and wait to let Tony take care of him, he’d already gotten himself off twice. Once in the shower because even a lukewarm shower wasn’t enough to discourage his dick.

By the time JARVIS called him down to the workshop, he had already been debating giving in a third time. He breathed a sigh of relief as the workshop’s doors opened for him.

“Come on in, Cap,” he heard Tony say from somewhere further back in the large room. “Toward the back on your right.”

Steve did as he was told, heading around into a part of the workshop he hadn’t paid much attention to before. When he finally found Tony, he stopped dead in his tracks.

Honestly, he wasn’t sure what to think upon seeing the setup that Tony had been hyping up for the past week. It looked like a cross between the examination tables he’d gotten used to in SHIELD medical crossed with a dentist’s chair. It also had a bunch of crazy and quite frankly intimidating attachments built onto it.

“Um… isn’t this a bit much?” He turned to Tony, expression wary.

Tony turned away from fiddling with something off to the side to face Steve. He had that manic expression that Steve associated with Tony lacking sleep. “Absolutely not.”

Tony went into a rant about how, apparently, the apparatus was fully maneuverable, tiltable, and could be raised to any height needed. There were also supports on the side, which Tony said with a wink would come into play later.

Steve crossed his arms. “I’m not even sure of what we’re doing, here.”

“Giving you the best orgasms of your life,” Tony said distractedly as he turned to a side table with what looked like medical implements on it. “This is 100% tailored to your comfort.” Tony gestured at the apparatus, which was set close to the ground now.

“So…” Steve gestured at the whole setup doubtfully. “What do you need me to do?”

“Strip,” Tony said as he set up what looked like a pullout tray attached to the bottom of the table.

Steve glanced around the workshop, feeling uncertain. It wasn’t like quickly undressing in front of Tony was something he hadn’t done before. In the space of the workshop, though, he felt… exposed, somehow.

His unease must have been written all over his body language because Tony moved to close the distance between them.

“Hey, big guy. Eyes up here.”

Steve didn’t even realize he had been avoiding Tony’s gaze. His eyes snapped back up to meet Tony’s.

“We don’t have to do this if you don’t want to, honey.” Tony ran a hand up Steve’s arm. “I’ll admit, I got caught up in the excitement, but we can table this for another time.”

Steve shook his head vigorously. He did want this. Not to mention that he’d already prepared and had a butt plug shoved up his rear. There was no way he was going to waste all this effort. “No, no. It’s not that I don’t want to do this.” He wasn’t sure exactly why he was hesitating, to be honest. “I guess it’s just… I just want to take time to ease into things?”

“Oh.” Tony stepped back to give him space, but Steve reached out toward his shoulder to stop him.

“How about you walk me through this?” Steve asked, hoping his look conveyed what kind of tone he was going for.

“ _Oh_ ,” Tony said, recognition alighting in his eyes. The corner of his mouth twitched up. “ _Well_ , then.” He started gently pushing Steve back toward the table. “In that case…”

Steve went easily, allowing himself to be pushed until his back hit the front of the table. He pushed himself up onto it automatically, leaving Tony standing in the vee of his hips. That also meant that Tony had a nice view of the bulge in his sweatpants.

Tony glanced up at him with lidded eyes. “How about you take off your shirt, and then we can get started?”

Steve did as he was told, pulling his shirt off of his head and tossing it off to the side. “And?” Steve asked, looking down expectantly.

“Lift your hips for a second.”

Steve did as he was told, knowing already what was going to happen. Though he wasn’t surprised when Tony grabbed the hem of his loose sweatpants and pulled them down along with his boxers, he still couldn’t help the gasp of relief as his cock sprung free and slapped against his stomach. He’d been leaking a fair amount of precome before; he was surprised it hadn’t shown through his sweatpants yet. But now it was there plain to see, and Steve could feel his blush spreading down to his neck. Out here in Tony’s workshop like this, as opposed to the bedroom, he felt like a specimen on display.

Tony’s expression only further drove the point home as he looked Steve up and down. “I will never, ever get tired of that.”

“T-Tony…” Steve said, his cheeks burning. Apparently feeling exposed like this did things for him because he could feel his cock harden further, too. More precome leaked down his shaft. He couldn’t help shivering.

“Sorry, let myself get distracted.” He gestured to what was behind Steve. “Move back a bit, okay? We still have to get that plug out of you.”

Somehow, Steve had almost forgotten in light of everything else going on. He did as he was told and leaned back on his elbows to give Tony access to his ass. He could only imagine what he looked like right now, with the end of the plug visible between his ass cheeks. Just the thought made his ears feel like they were on fire.

Tony leaned forward. “Mmm, yeah, that is settled in there real nice, isn’t it?” Steve flinched when he felt Tony’s hand on his ass cheeks. “Used one of the medium-sized ones, too.”

“Y-yeah. Just like you said.”

“Perfect,” Tony practically purred. Steve nearly jumped when he felt Tony’s finger prod the base of the plug. “Though we both know you can fit much, much bigger in you, don’t we?”

Steve nodded, though he wasn’t sure if Tony could see it. “I-I can.” He took a sharp breath when Tony pulled on the plug a little.

Tony continued to move it around while murmuring praise; saying how good Steve was at taking the plug. How nicely stretched his hole was. He pulled it slowly, stopping for a bit at the widest part, seemingly listening for Steve’s harsh breathing. Steve cried out when he finally pulled it loose with a wet pop.

“You did such a good job,” Tony crooned as he ran a hand up Steve’s leg. “Now just lie back and relax. I’ll take care of everything from here.”

Once he was on his back, he noticed Tony pull something out from underneath the table’s surface. They turned out to be padded stirrups that folded out from the base of the table. Tony directed him to scoot forward and raise his legs up so that he could secure Steve’s legs and feet in the stirrups. Like this he was on display with his ass right there for Tony to see. Tony moved around next to direct Steve’s arms to the straps on the sides of the table.

“Isn’t this a bit much?” he asked, feeling a bit uneasy as Tony strapped his arms in.

“It will be necessary, believe me.” Tony planted a kiss on his forehead from the side. “Besides, this isn’t the first time I tied you up, now is it?”

Steve couldn’t help the deep groan as he shut his eyes at that. He felt his cock twitch as his eidetic memory helpfully brought up images of all the times he’d let Tony tie him up.

“True...” he answered, his voice shaky.

When Steve opened his eyes again, Tony was standing in front of him and pulling on white latex gloves as he turned toward a tray off to the side. Steve could just make out a container of some indistinct substance before he closed his eyes again. He’d rather not know too much about how all this worked. Instead, he focused on easing up and letting himself just enjoy this. Tony would take care of everything, and he trusted Tony to make this good, as bizarre as it all was.

“You’re going to feel something weird,” Tony said from where he was fiddling off to the side. “Probably a little cold. Definitely slippery. Try to relax into it.”

Steve opened one eye just to get a sense of what Tony was about to do. He walked around to where Steve was precariously exposed with something that looked like a hose in his gloved hands. Steve wondered if he should ask but then thought better of it. He flinched at the first sign of something prodding at his hole and then quickly relaxed like Tony had told him to.

“There we go,” Tony said in a soothing tone. “Just like that.” He ran a hand along Steve’s thigh almost as though he was rewarding him. “You’re being so good for me, Steve.” He glanced up from what he was doing to meet Steve’s eyes. “You’re always perfect for me, aren’t you?” He added with a chuckle.

Steve groaned at Tony’s words. His cock had flagged a bit when Tony had started strapping him to the table, but now he was getting hard again.

It seemed that Tony noticed as his eyes trailed down. “Already getting into it, huh?” His expression turned devious. “You really are a needy little cock slut, aren’t you?”

“ _Tony_ ,” Steve cried out as he strained in his bonds.

“We haven’t even gotten started and you’re about ready to go off, huh?” Tony’s hand that had been on his thigh moved down to caress the curve of his ass. “Don’t worry, I’m almost ready.”

“You are?” Steve couldn’t help asking. Now that his arousal had rekindled, he found himself getting antsy.

Tony stepped back. “Pretty much.” He turned toward a holographic screen that Steve hadn’t noticed until now. “On my count, in 3… 2… 1…”

Steve felt something like a jolt in his ass as the hose or whatever the hell it was went taut. He wasn’t sure what to expect until he felt something slightly warm and wet enter him. He couldn’t help tensing up at the unfamiliar sensation.

Tony’s gloved hand was back on his thigh. “Relax, champ. Just some sterile gel that’ll ease the way for what’s coming next. And believe me, you’ll want to be ready for that.”

Steve couldn’t help a nervous, almost hysterical chuckle as he did his best to comply. “I’m starting to wonder just what the hell I signed up for.”

“You’ll see.” There was a notable pause before Tony added, “Or, well, I guess you’ll _feel_ it. Won’t be long, now. You’ll like this, I promise.”

Tony was one to always follow up on his promises, especially in bed, so Steve did his best to obey as he got used to the feeling of the gel in his ass. A few more moments passed before that gel gave way to something _different_.

“Oh God, what is that—” He flinched as the strange sensation quickly became a strong pressure. It seemed to increase rapidly every second until it felt like even Steve’s stretched hole wouldn’t be able to accommodate whatever this was.

The soothing touch of Tony’s hand on his thigh helped to ground him. “Just a bit of the technology I explained to you,” he heard Tony say softly. “Like I said: kind of like a dildo, but much, much better. And don’t worry, I made sure the diameter of this one was enough to make you have to work for it, but nothing close to anything that’d hurt you.”

The pressure seemed to stabilize as Steve exhaled heavily. He thought back to the diagram he’d seen a few days ago and realized just what the object must look like. Even with the ample amount of preparation he’d had, though, this was a tight fit. He grunted as what be an egg-shaped object continued to push until suddenly the pressure was gone as it passed through the tight ring of muscle. He gasped as he felt it slip inside.

“You okay?” Tony asked, a tinge of concern in his voice.

To be honest, Steve wasn’t sure of how to answer right at the moment. Now that the pressure had abated, he realized he was fully hard. The sensation of its pushing had been tense, but the way it had forced itself past the tight ring of muscle felt good, too. The pressure was still there, though, as whatever had been pushed into him seemed to be moving slowly.

“Yeah,” Steve gasped out. “Just… really weird.”

He heard Tony chuckle again. “Yeah, it’ll take some getting used to. But that wasn’t even the best part.”

Pleasure shot through Steve’s nerves before he even realized what was happening. His eyes flew open and he cried out as the thing inside him started to vibrate right up against his prostate.

“ _That’s_ the best part.” Tony sounded very proud of himself.

It was like nothing else Steve had ever felt in his life. He writhed against his restraints, the stimulation almost too much to handle. Whatever the object was, it was like it knew exactly what he needed. He cried out again as he came hard, his release spattering his chest and belly. The orgasm was intense as the thing inside of him seemed intent on driving him insane. Finally, the vibrations ceased as Steve came down from his climax.

Panting heavily, he could only lie still and groan softly as the object continued to travel further inside him.

“Feel that?” Tony asked, his tone the same as when he was explaining a new breakthrough in his armor’s tech. “It responds to your body heat and changes shape once it’s deep enough inside of you. Peristalsis takes care of the rest.”

Steve couldn’t help squirming. He could still feel the egg moving through him. While not painful, it was an odd sensation. He tried to relax his abdominal muscles, and once he did, the sense of strangeness gave way into a more pleasant sense of fullness. Steve groaned as he loosened up a bit more and just let himself feel the slow movement of that fullness in his gut.

Tony smiled down at him. “You can still feel it moving inside of you, huh? Like I said, it’s peristalsis—all those circular gastrointestinal muscles contracting to push it through you. So you’ll feel it the whole way through.”

Steve huffed out a laugh. “That wasn’t so bad.”

“In that case...” He patted the curve of Steve’s ass lightly. “Does that mean you’re ready for round two?”

Steve nodded before Tony had even finished speaking. “Let’s keep going.”

Tony looked pleased as he chuckled. “There is definitely more where that came from.”

As if on cue, Steve felt yet another egg-shaped object push against his entrance. He cried out again as it pushed against the tight ring of muscle. Even after having been eased open by the first one, it took a bit for the second to reach its widest point. By then, Steve was moaning, his eyes shut as he tried his best to allow the intrusion.

“Relax,” he heard Tony say again as the egg pushed through his hole.

“Easy for you to say,” he gasped out. “Just... give me a second.” He focused on relaxing his whole body. Once he did that, the egg slowly started to ease its way through. “Oh god,” he said as what felt like the widest part passed through him.

“Just a bit more,” Tony assured him.

It wasn’t painful—the last egg had ensured that he’d be prepared for this one—but the pressure was still immense.

He was surprised when it finally slid all the way in with a brief popping sensation. Throwing his head back, he let out a groan of relief. He was just calming down when he felt the intrusion hit his prostate again, making him jolt upward in his restraints.

His cock had barely flagged after his last orgasm and seemed to be having no trouble whatsoever getting back to full mast. This time the egg passed through before Steve went over the edge. He was keyed up and desperate to come by the time third egg-like object was pushing its way into him. Once it reached its widest point pushing against his entrance, he was gone. His back arched off of the table when he came. When he finally settled down, he was starting to actually sweat.

“Mmmm,” he heard Tony practically purr. “I will never get tired of watching you like this.”

He wanted to laugh, but he couldn’t even get a sound out before the fourth egg was pushing against his hole. It was obvious by this point that they were gradually increasing in diameter so that each intrusion felt as intense as the last one. The vibrations against his prostate only got more arousing as he started to feel oversensitized. He let out a low groan, his cock twitching as the egg slowly shifted past and the vibrations ceased. With four off the egg-shaped objects inside of him now, he could feel all of them moving inside of him. He felt full, and Tony didn’t show any signs of being finished yet.

Steve lost track of time after that as at least two more objects forced their way inside him. He barely even noticed Tony removing the hose afterward. Some time after, he felt an odd sensation when Tony’s hand stroked his abdomen, prompting him to moan. He felt high on pleasure, and there was a faint buzzing in his ears. His lips curved into a smile as he gazed up at Tony.

“You took it all so well,” Tony said in a reassuring tone. “You are so wonderfully sensitive, too. Bet you can feel exactly how full you are, right now.”

That was when Steve glanced down and realized why Tony’s hand felt different. There was a definite bulge to his stomach, smoothing out the usually well defined lines of his abdominal muscles.

“Oh,” he said quietly as he finally started to process the fullness that had settled in his gut. He forced himself to relax his abdominal muscles again and focused on the sensation of the eggs still shifting inside of him. It was so damn good, and Tony’s hand stroking back and forth over the raised skin of his abdomen only made it better.

Chuckling, Tony smiled. “Yeah, ‘oh.’ How’s it feel?”

Steve blinked a few times in an attempt to clear his thoughts before answering, “Good, Tony. So good. I… I’ve never felt anything like this before.”

It was as honest an answer as he could think to give. He imagined he’d be feeling full, but he never could have imagined _this_. He was still squirming a little as the eggs continued to be pushed through him. He was warm all over, as though he were lying in a tangle of blankets made out of the softest material imaginable. And every time Tony’s gaze raked over his body, it was like his skin was on fire. He trusted Tony to take care of him, and it was like a burden was lifted from his shoulders.

Tony slid his hand upward to stroke Steve’s chest. “Do you think you could take a bit more?”

“There’s more?”

“Well…” Tony glanced away briefly before looking back at Steve. His pupils were dilated, almost completely overtaking the brown. “I told you this is nanotech. It can do… a lot. Right now they’ve taken the form of something compact to make it easier to move inside you. But now that they’ve settled, they could… expand.”

Steve couldn’t help laughing, though it sounded delirious and almost manic to his ears. “Tony, you’re really something else. You know that?”

For once, Tony actually looked bashful as he ducked his head. “Could say the same about you, big guy.” He seemed to hesitate before asking, “So… is that a yes?”

Steve nodded fervently. “Please, Tony. It feels so good right now, but I want _more_.”

He felt Tony’s groan more than heard it as Tony rested his head on his chest. “God, Steve. You can’t just _say_ things like that. It isn’t good for my heart.”

“I think you’ll manage,” he said with a strained smile.

Tony pushed himself up and winked at him. “Maybe,” he said as he laughed softly. Glancing over at some readout floating in the air above Steve’s head, Tony nodded to himself. “It starts to hurt and you tell me, okay? I’ve tested this, but better safe than sorry and all that.”

Steve nodded again as he let his head sit against the headrest. “Do your worst, Stark.” He already so full, but he wanted more than anything to keep going.

That got him a nice grin, all teeth, from Tony. “You got it, Cap.”

He didn’t notice anything at first. Tony just kept idly stroking his stomach as he peppered kisses over his chest. Occasionally his hand would stray up to tweak one of Steve’s nipples, which would make Steve writhe in his restraints. Maybe that was why he didn’t notice things sooner.

His breath hitched when the increase in pressure in his abdomen seemed to hit him suddenly. It wasn’t long before the sensation was incredibly strong and everywhere at once. A slight cramp flared up, making Steve gasp—only to elicit a moan a few seconds later as it somehow added to the pleasure that was already building up low in his gut.

“Mmm,” Tony hummed as he lightly caressed the bulge in Steve’s abdomen. “You feel that? I bet you do.” He chuckled, his voice low. “Hell, you can even _see_ it now.”

Steve glanced down at his stomach again and gasped when he realized Tony was right. He could see the way his stomach was swelling even further under Tony’s hand. Really, it should be alarming, Steve distantly thought to himself. Instead, it was the hottest thing he’d ever seen. His cock certainly agreed with him, not even letting the amount of times he’d already come deter it from filling out again in record time.

“A-Ah,” he gasped as the pressure continued to increase and his abdomen bulged out more. His back arched as he struggled against his restraints. It was too much, yet so, _so_ good at the same time. He almost missed Tony asking him if he was okay or not.

“I’m fine,” he answered through gritted teeth.

“Good, good,” Tony said in a soothing tone. “Almost done, champ. You’re doing so well for me. Taking so much like this.” He was still gently stroking the stretched skin of Steve’s abdomen. “Getting so big like this. Damn, you’re really something else.”

Steve’s next orgasm hit him so hard he nearly blacked out. It seemed to go on forever as the tight pressure in his core practically forced it out of him. He was sweating profusely now as he focused on keeping his breathing even. That seemed to be the best way to deal with the pressure so that he could focus on the pleasure. He felt like he was floating, his entire body going lax as he felt the aftershocks from one of the best orgasms of his life.

He finally opened his eyes when he felt a faint tickling sensation. Tony was leaning over him, swiping a finger through the mess on his stomach and chest. He groaned at the sight alone as Tony licked his fingers. The tender skin was oversensitized so that even the the soft glide of Tony’s finger over it was almost overwhelming.

After settling back, Tony started unceremoniously removing his shirt. He moved onto his pants next. Even in his post-orgasm haze, Steve couldn’t miss how impressively Tony’s erection tented the front of his briefs. Tony turned to him with a sultry look before slowly pulling them downward. His cock sprung free, already fully erect and flushed red. Just the thought that Steve had done that to Tony without even touching him was enough to make him moan.

Tony slowly ran a hand down Steve’s leg to his ankle as he circled around to his front. “You’re irresistible like this, you know. Well, you’re always irresistible. But…” His gaze met Steve’s and the fire in it made Steve shudder with anticipation. “Right now I just really want to ride you.” He hopped up onto one of the supporting steps below the apparatus so that he was standing over Steve. He glanced down at him with a predatory grin. “And you’re going to lie there and let me enjoy your big, fat cock, aren’t you?”

Steve felt his skin flush all the way down to his chest at Tony’s words and nodded.

“That’s what I like to see,” Tony said as he lowered himself slowly so that he was hovering over Steve. “You’re being so, so good for me, Steve.”

Steve moaned at the praise and strained against his restraints. He could feel his cock twitch against his sensitive skin.

Tony positioned himself in between Steve’s legs in the stirrups. From what Steve could tell, there was just enough space for him to stay on his knees comfortably. As Tony steadily adjusted the position of the stirrups, some distant part of Steve’s mind that wasn’t dealing with the onslaught of sensations wondered if Tony planned this when he designed this whole setup. Knowing Tony, that was probably the case. He couldn’t help smiling to himself as Tony leaned forward to kiss him.

Pulling back, Tony returned his smile. “You’re pretty far gone, huh?” Steve shuddered when Tony stroked the side of his face tenderly. “You okay?”

“Yeah,” Steve responded. Speaking always felt like a lot of effort when he was like this.

“Good,” Tony said with a nod before settling back on his knees. He produced some lube seemingly out of nowhere and squirted some out onto one hand. It wasn’t long before he was reaching behind himself, letting out a gasp soon after. Turning his attention back to Steve, he said, “Won’t be too long, now.”

Steve nodded. He settled back and watched as Tony closed his eyes and started to finger himself open. As Tony moaned and gasped and shuddered above him, he wished he could reach up and kiss him or just pull him against his chest or something. But he felt so sluggish, all of his energy seemingly sapped by the heavy weight in his abdomen. It was nice, though. With the serum he always felt like he had an excess of energy. For the first time he could remember, he was able to just relax and let go in a way he never had before.

He wasn’t sure how much time passed before he heard Tony’s voice again.

“You with me, sunshine?”

Steve nodded again.

Tony gave him a lopsided smile. “Look at you, all sweet like this.” His tone was so tender and reverent that Steve couldn’t help groaning. “Can’t wait to feel you inside me.”

“Please,” Steve gasped.

“As tempting as it is to just sink down on that nice, big cock of yours, I’ve got this all planned out. So just bear with me for a bit more, okay?”

Steve could only nod. Whatever Tony wanted to do, it had to be good. Steve trusted in that more than anything right at this moment.

He flinched when Tony squeezed out a small bit of lube onto Steve’s stomach.

“Gonna need this later,” Tony explained as he spread it around with his fingers across Steve’s oversensitized skin.

“ _Tony_ ,” Steve panted as he writhed against his restraints. His cock twitched against the underside of his belly, slick with precome. He’d lost count of how many times he’d gotten off by this point, but it felt like he could keep going forever.

“There we go,” Tony said in a soft, reverent tone. He smiled down at Steve before saying, “Do you have any idea of how gorgeous you are like this? Wish you could see yourself right now. Such a perfect mess for me. Never seen you give yourself up so completely like this before.” He reached down and stroked his own cock once with the hand covered in lube and moaned. “I could get off just watching you like this. But that wouldn’t be as much fun, now would it?”

Steve shook his head. He wanted to feel Tony all around him. Covering him and his full, full belly.

Tony took that moment to reach down to slick up Steve’s cock, his fingers wrapped lightly around Steve’s dick as it moved up and down. “I’m going to take you now, okay?”

Steve blinked a few times before meeting Tony’s gaze and nodding.

Tony used one arm to brace himself against the armrest and the other to hold Steve’s cock in place. He gave Steve a sly, lascivious smile before sinking down slowly.

Steve couldn’t help it, his back arched again as he sought out Tony’s heat on his cock. They groaned in unison when the head of Steve’s cock finally pushed through the tight ring of muscle. Even after all of his preparation, Tony was so wet and _tight_.

Between the intense pressure in his abdomen and the feeling of Tony sinking down on his cock, Steve couldn’t even bring himself to form words. It felt like there was hardly any room in him left for air, let alone wasting any of it on speech.

“Fu-fuck, I always forget how big you are, somehow,” Tony said breathlessly. Closing his eyes, he focused on pushing down further, taking Steve in inch-by-inch. For a while, the room was silent except for the sound of Tony’s occasional grunts and the rush of blood in Steve’s ears mixed with his own heavy panting.

It seemed to take forever for Tony to finally sink down all the way. Steve gasped when he felt Tony’s warmth settle against his balls.

“Oh, fuck,” Steve managed to get out, his voice rasping and heavy.

Tony gave him another soft smile. “Glad to hear you’re enjoying yourself. I’m gonna move now, okay? You don’t need to do anything. Just… focus on how good everything feels.”

“Mhmm,” Steve hummed back.

Tony’s upward slide was just as good as his muscles clenched down on Steve’s cock as though reluctant to be empty again.

And then Tony leaned forward, covering Steve with his warmth. It was an awkward angle, what with Steve’s swollen abdomen in the way, but Tony was able to hold himself up by the armrests and settle over Steve’s chest. He smiled down at Steve.

“Hello there.”

Steve couldn’t help laughing at Tony’s ridiculousness. “Hi,” he replied.

“Feeling good?”

Steve nodded. “Very good.”

“Ready to feel even better?”

Steve hummed in agreement.

With his arms on the armrest supporting him, Tony started pushing back down onto Steve’s cock. Leaning over him and being this close meant that Tony’s cock rubbed against Steve’s abdomen.

Steve let out a long, loud groan at the contact. With his stretched skin as oversensitized as it was, it felt like he could feel every bit of Tony’s thick, hot flesh. Now he understood why Tony had applied lube there before starting.

“Bet you’re pretty full, huh?”

Steve groaned, his head hitting the headrest with a faint thud. “So damn full,” he murmured in agreement.

“You feel so goddamn good like this,” Tony said as he started to move a bit faster. “So full for me. Fuck, Steve, you’re so good to me.” He followed up with a particularly hard thrust against Steve’s abdomen.

Steve cried out at the contact, back arching against his restraints.

“Mmm, yeah, just like that, Steve,” Tony coaxed him as he continued rubbing off on him. He set a rhythm; pushing down onto Steve’s cock and then pulling off to rub against Steve’s swollen belly. The lube kept the slide against Steve’s tight skin easy as Tony pressed his lips against Steve’s chest every time he rubbed against him.

It didn’t take long for Steve to reach his climax, jerking his hips upward into Tony and crying out as he came hard inside him. Tony kept riding him, his face buried in Steve’s chest as he panted hard. He was moaning Steve’s name and an assortment of endearments and expletives that Steve couldn’t really make out with all of the overwhelming sensory input. It wasn’t long before his rhythm stuttered and he came hard with a grunt against Steve’s skin, his cock spurting warmth between them.

Tony continued to lie against Steve’s chest, his own chest heaving as he regained his breath.

They both rested there for what felt like a long time to Steve. He was still pretty far under. The only thing really registering at the moment was the heat of Tony’s skin against his own and the unrelenting fullness in his abdomen.

Tony finally stirred, slowly pushing himself up from Steve’s chest. He had this dopey smile on his face that Steve wanted to kiss so badly.

“How’re you feeling, honey?”

Steve couldn’t help smiling at the pet name. “Amazing.” Except there was something that felt off. “But um… I’m kind of thirsty.”

Steve didn’t miss the way Tony’s expression softened.

“Of course!” Tony ran a hand through his hair in frustration. “Geez, I’m not being very considerate, am I? Here you are sweating up a storm and I haven’t even offered you anything to drink.” He winced as he pushed himself off of Steve, and they groaned in unison when the head of Steve’s cock finally pulled free. Tony gave him an apologetic smile. “Guess I got carried away, seeing you like this.”

Steve couldn’t help chuckling, as much of a strain as it was. Tony actually looked embarrassed for once.

“It’s fine, Tony. I… I’ve really enjoyed this, too, you know.”

“Yeah?” Tony asked, looking a bit uncertain.

Steve nodded. “But I wouldn’t say no to a drink or something.”

“Coming right up,” Tony assured him with a pat to his arm before he dashed off to the mini fridge that he kept stocked in the workshop.

Steve let himself sink back into the sea of sensation that he’d been floating on for so long, now. He was still so _full_ ; more full than he’d ever imagined he could feel. It was everything he’d hoped for and more because it was Tony, and Tony always took such good care of him. After all, the nanites were Tony’s technology; so just like the suit, they were an extension of him. The fact that he was carrying them inside of himself like this made him feel hot all over. He was definitely aroused, but not in the way he was used to. It wasn’t all centered in his abdomen and his dick, for once. Instead, his entire body buzzed with a pleasant lassitude.

He was taken out of his thoughts when he heard Tony approach. Glancing up, Steve noticed that he’d pulled on a pair of slacks. He smiled when he felt Tony’s fingers lightly caressing his cheek. “Got you a nice cold sports drink. Figured you probably need some electrolytes after all this.”

Steve turned his head toward Tony. “What flavor?”

Tony returned his smile. “Your favorite: generic blue flavor.”

Steve huffed out a laugh. “You know me so well.”

He was surprised when Tony brought a crazy straw to his lips. It seemed like a bit much, but he was grateful all the same. Steve savored the sensation of Tony running his fingers through his hair as he emptied the bottle. After Tony took the straw away, he let Steve rest for a bit before he came back to the table and patted his knee to get his attention.

“So here’s the deal,” Tony said softly to him as he continued to run a soothing hand over Steve’s abdomen. “We can get the nanites out of you the easy way or the fun way.”

Steve blinked at him, turning his head against the table that was slick with his sweat now. “What’s the fun way?”

Tony chuckled. “Should’ve known you wouldn’t go for the easy way.” He moved his hand down toward Steve’s soft cock. “Well, for your information, the easy way would just to be have them go back to a more… fluid form and have you push them out that way. The fun way…” His hand passed down below Steve’s balls toward his perineum. “The fun way is to have you push them out just like they went in.” Steve flinched when Tony’s fingers reached the loosened ring of muscle and pushed inward. “You’re still a bit loose down here. I think you could pull it off.”

Steve groaned, the thought of pushing everything back out making his cock twitch and stiffen up a bit. He was so exhausted; just taking in everything had taken so much out of him. He could take the easy way out, and he knew Tony wouldn’t think any less of him for it. At the same time, though, he couldn’t ignore the challenge in Tony’s voice. He opened his eyes to find Tony looking at him expectantly, his eyes heated with excitement. He wanted to do this, just to prove that he could. Even if it wouldn’t be easy, he knew it would be enjoyable.

“Let’s do it, then.”

Tony’s eyes widened briefly before he started laughing. He was glancing down at his hands on the edge of the examination table. He raised his head to smile at Steve. “God, I love you so much.”

Steve smiled back. “Don’t get sappy on me now, Stark.”

Shaking his head, Tony kept laughing. “You must be rubbing off on me.” He ran a hand through his hair before turning away. “Let me just get a few things ready and get a new pair of gloves.”

Steve drifted off a bit more, just barely paying attention to the sound of Tony preparing things off to the side. Tony’s hand on his abdomen forced him to focus his attention again.

“Okay, champ. This is going to be fairly simple.” Tony considered his words for a moment. “At least, in theory. All you have to do is push and they’ll come out. They’ll keep a shape that’ll move fairly easily, but will still take some work to push out.”

Steve nodded, though he had one question. “Um… will they still…” He felt awkward even trying to finish the question.

“Will they vibrate against your prostate?” Tony asked with a laugh. “Sure. Wouldn’t be nearly as fun if they didn’t, right?”

Steve could feel his face heating up again. He wasn’t even sure how he could be embarrassed after all of this, yet here he was.

Tony kept a hand on Steve’s stomach, idly rubbing soothing circles into the stretched skin. “Now, then. Are you ready?”

“Yeah, I’m ready.” Steve wasn’t sure exactly what Tony needed to do on his end, but he assumed that they both needed to be on the same page.

“I’ll tell you when to start pushing.” Tony glanced up at a screen somewhere above Steve’s head and seemed to be counting to himself. A few moments later, he started saying the numbers out loud. “In five seconds: four, three two, one… Start pushing now.”

Steve did as he was told and focused on contracting his abdominal muscles. Another nice benefit of the serum was that he had more precise muscle control than most people. He wondered how difficult this would be, all things considered.

He gasped when he felt the eggs moving inside of him again. He thought maybe he’d gotten used to them, but they felt different once they started moving. Probably something to do with how they changed shape, as Tony had explained.

It seemed to take forever for the first one to travel back to his entrance as he continued to push, his whole body straining as he focused. He wasn’t sure exactly where it was until he felt a strong jolt from his prostate.

“Oh god,” he said with a groan as the first egg started vibrating as it brushed past his prostate. He could feel his cock start thickening up again, painfully.

Tony chuckled as he continued to run soothing circles over Steve’s stomach. “Sounds like you’re almost there.”

Steve cried out as the first egg reached his rim. The vibrations had stopped, but now the egg was stretching the tight ring of muscle all over again. He kept pushing, his chest heaving from the effort. By now, he was sweating heavily to the point that his skin shined in the bright lights of the workshop. Gritting his teeth, Steve continued to push as the widest part of the egg passed through his rim. And then just like that, the pressure was gone as the egg came out completely and landed on the tray below with a wet thump.

Despite how worn out he felt, Steve almost forgot how to breathe when he looked up and saw Tony’s expression. He looked entranced as he stared down at what must be Steve’s gaping asshole.

“Holy shit, that was _hot_ ,” he said, tone breathless. His gaze drifted upward to meet Steve’s. “I know this sounds weird, but watching you do that was kind of… beautiful?”

Steve laughed at the wonder in Tony’s voice. “Well, like you said earlier… there’s more where that came from.”

Tony’s eyes were half-lidded as he glanced between Steve’s face and his ass. “I might have to record this some time. Fuck, you’re gorgeous.”

“Only if I get to watch,” Steve added with a small smirk. He was gratified when Tony nearly choked on his own breath.

“Even stuffed full of nanites, you’re a damned menace,” Tony said as he shook his head. He stepped forward and ran a gloved hand along Steve’s leg, moving up toward his abdomen. “Let me help you.” His hand settled softly on the still sizeable curve of Steve’s belly. “Can’t let you do all of the work, after all.”

Steve couldn’t help smiling. “So nice of you to offer.” He groaned when Tony started lightly stroking his stomach. “Okay, yeah. Keep doing that.”

Tony smiled back at him. “Ready when you are.”

Steve nodded and then turned his focus back to his abdominal muscles. Once again, he felt the objects moving through him until one of them reached his prostate again. Even when he was prepared for it, the vibrations made him gasp and writhe. He was hard and leaking again, adding to the mess on his stomach. By the time the egg was halfway through being pushed out of his hole, he hit his peak.

There was a loud shout that he realized belatedly must’ve come from him as he strained against his bonds in his throes of ecstasy. By the time the aftershocks of pleasure had passed, he glanced down to see even more of a mess on his stomach. And to his surprise, he’d managed to push the second egg out.

He flinched when he felt Tony’s gloved hands probing around his entrance. Glancing down, he could only see the top of his head.

“Sorry,” Tony said as he kept his attention on Steve’s ass. “Just seeing if I can make it easier for the next one.”

Steve did his best to remain still as he felt Tony gently poke around.

“Okay, I think I’ve got this. Feel free to start again when you’re ready.”

Steve didn’t waste another moment and started pushing again. He groaned as he felt yet another object move through him until it passed his prostate, at which point he gave into the overwhelming pleasure that burned through him, from his core to the tips of his fingers. He was beyond oversensitive by now, yet his dick didn’t seem to care: it was already half hard and seemingly ready for another round.

By the time it reached his entrance, Steve was moaning, sweat running down the side of his face. He was riding a fine line between pleasure and pain to the point that he wasn’t sure he could tell the difference between them anymore. All he knew was that he wanted more as he kept straining his muscles.

“That’s it,” Tony said encouragingly. And then Steve felt Tony’s fingers against his hole and suddenly the egg was halfway out, much faster than the previous two had gone. “Just helping you out here a little, okay?”

Steve’s response was cut off when the egg finally passed through the resistance of his entrance. Relief washed over him, so strong it was almost like an orgasm in and of itself. He glanced up at Tony, who smiled at him. Or at least, it looked like a smile. The edges of his vision were fuzzy, and he felt oddly detached from his own body. It was nice, though. Like he was floating and everything was just flowing through him.

Before he even realized it, the fourth object hit his prostate. He was so close already, and it was driving him crazy. Even as the object started to emerge out of his entrance, he couldn’t quite reach his climax. With Tony’s help, it didn’t take long for it to come out, leaving Steve gasping in frustration. And then he felt a warm, callused hand wrap around his dick and he gasped as that tipped him over the edge.

He tried to curl up before he remembered the restraints holding his arms and legs. Instead, he turned his head to the side and shut his eyes. His orgasm seemed to be going on forever as he whimpered into the table’s surface.

“You okay, honey? We can stop here, if you need to.”

Eyes still shut, Steve shook his head. “N-no, wanna get them all out. F-feels so good, Tony. Just… s-so much, too.”

He felt Tony’s hand start to rub soothing circles into his abdomen again. Gradually, he willed himself to calm down before he started to push again.

The last two took a bit longer to push out, but with Tony’s assistance and his other hand on Steve’s dick keeping him hard, Steve managed one more orgasm just as the last one passed by his prostate. He was so overwhelmed by this point that he didn’t realize he’d come until he glanced down to see Tony’s hand still on his cock, dripping with his own release.

He groaned when Tony raised his gloved hand to his mouth to lick off his come. “Mmm, that was so sexy to watch, honey. You have no idea.”

“Glad you enjoyed it,” Steve murmured. He could feel the corners of his mouth stretching into a weary smile. Now that he’d pushed the last one out, exhaustion hit him like a truck. “‘m gonna take a nap now.” The last thing he saw before closing his eyes was Tony’s soft, fond expression.

 

* * *

 

Steve woke up feeling lethargic, every muscle in his body lax. His sense of his surroundings filtered into him bit by bit: the warm, soft bed sheets and blanket surrounding him, the solid thigh his head was leaning against, and finally the soft pressure of someone caressing his scalp. He could hear faint vibrations, which meant Tony was probably on his phone and they were probably in bed. He must’ve been out for quite some time.

Keeping his eyes closed let him focus on everything else: he was warm and dry, which meant that Tony must’ve cleaned him up afterward. He smiled to himself at the thought.

Moving seemed like far too much effort at the moment, too. His muscles felt like liquid, yet heavy at the same time. He was content to just lie there and let himself be, for once. Tony’s fingers carded through his hair gently, and it felt so good it traveled all the way through him. He groaned as his toes curled under the sheets.

“Finally awake?” Tony’s voice was gentle.

“Mmm,” Steve answered as his tongue seemed to not want to cooperate yet.

“Oh man, that really took a lot out of you, didn’t it?”

Steve pushed his head up into Tony’s hand. “Mmhmm.” He couldn’t remember the last time he’d felt so completely drained like this. It was almost like he was still floating, though he was far more grounded now than he had been back in the workshop. He let out another groan from deep in his throat when Tony’s fingers pushed back through his hair. Usually even this much stimulation was enough to get him aroused. Now, instead of all of that sensation going right to his cock, there was just a nice, pleasant heat simmering under his skin.

“Sounds like it’s something we should try again some time, huh?”

Steve nodded against Tony’s hand. It had been a lot of work, but it was worth it.

“Did your dick _finally_ throw in the towel?”

“Don’t ruin the afterglow, Tony,” Steve eventually answered after a minute.

“I’m just soliciting feedback!”

“Ten out of ten, would let you put nanotech in my ass again.” Steve opened one eye and turned his head to look up at Tony. “How’s that for feedback?”

Tony’s smile was soft and unspeakably fond. “I’ll take it into consideration.”

Chuckling, Steve turned his face back toward Tony’s thigh. It wasn’t long before Tony’s fingers against his scalp lulled him back to sleep. His last thought was how lucky he was to have someone as ridiculous, wonderful, and brilliant as Tony Stark in his life.

**Author's Note:**

> Thank you for reading! Comments and kudos are welcome and very much appreciated.


End file.
